Sleep 101
I have always valued my sleep, but the sleep deprivation that came with motherhood for me, made me so much more aware of just how much sleep matters. After all, this is the time of the 24 hour cycle where we do the majority of rebuilding and repair. It is no wonder then why poor sleep is routinely linked to chronic disease.
Still, sleep is often taken for granted until we realize we are lacking it. Not only does sleep provide our bodies a specific time dedicated to repair and recovery, but it also equips us with an opportunity to organize short-tern memory into long-term memory, and process and filter the images, feelings, and conversations of the day. And when we really dig into the anatomy and physiology of sleep, we find quite an amazing story.
Sleep Phases
Sleep takes place in phases, that are not exactly linear. The first, called sleep onset latency, is the period it takes us to go from awake to unconscious, and is normally between 10 and 20 minutes. Next, Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) set in, with rotating, and repeating 90-minute cycles. NREM cycles are longer in the beginning, and slowly become shorter, while REM cycles grow in length of time from the start of sleep until we wake.
Circadian Rhythm
The suprachiasmatic nucleus, a bundle of nerves located within the hypothalamus, is the primary site of our circadian clock. This nucleus is responsible for the regulation of many biological rhythms including wakefulness and sleep, digestion, and body temperature regulation. Located in close proximity to the optic nerve, the suprachiasmatic nucleus receives input from cells of the retina in response to exposure to light and darkness. This in turn activates corresponding hormones.
Hormones
Cortisol
Our alert/wakeful hormone that is stimulated by light, particularly blue light waves, signaling time to rise and be productive
Essential to acute stress response-cortisol is released as our body’s normal reaction to stress as part of the fight-or flight
Anti-inflammatory-manages inflammation caused by physiological stressors
When chronically activated by chronic stress or poor diet can lead to cortisol resistance and chronic inflammation
Melatonin
Activated by onset of darkness and continues to be produced throughout the night
Should be low in the morning and throughout the day
Acts as a potent antioxidant especially locally within the brain
Repressed by artificial light especially toward evening
Human Growth Hormone
Most active while we sleep
Responsible for repair and growth of tissues-very active in rapidly growing children
Builds muscle mass boosting metabolism
Nutrition For Sleep
Protein -provides the essential amino acid tryptophan needed to make both serotonin and melatonin; also provides the amino acid glycine which acts as a neurotransmitter with an inhibitory effect aiding sleep
Carbohydrates-Late night eating, especially refined carbs, elevate blood sugar too close to sleep, causing a blood sugar crash during sleep that can be disruptive to quality sleep
B vitamins-B6, B12, and Folate especially, are essential to a methylation pathway of which melatonin production is dependent
Leafy Greens
Eggs
Salmon
Legumes
Vitamin D-Involved in melatonin synthesis. Vitamin D is best absorbed from sun exposure approximately 10-30 minutes a day midday without sunscreen
Fish
Egg yolks
Fortified foods
Magnesium-involved in more than 300 biochemical reactions, this mineral regulates many other important chemicals involved in sleep including melatonin and GABA (a calming neurotransmitter)
Dark chocolate-unsweetened preferably
Avocados
Nuts and seeds
Leafy greens
Iron-acts as a cofactor to melatonin-essential to melatonin synthesis
Dark chocolate
Red meat (in moderation)
Red kidney beans
Vitamin C rich foods taken with iron rich foods increase iron absorption
Caffeine
Caffeine is similar in structure to adenosine, the molecule that builds up throughout the day to promote sleep drive-in this way it can block adenosine receptors and their action
Avoid caffeine after noon
Try replacing coffee/caffeine slowly with tea, lemon water, or meditation to allow for your body’s own natural cortisol to get you going
How Much Sleep Do We Need?
Infants 14-17 hours per day
Toddlers 11-14 hours a day
Preschool Age Children 10-13 hours
School-Age 9-12
Teens approximately 8-10 hours
Adults 7+
Sleep Hygiene
There are many lifestyle adjustments that we can make to improve our sleep quantity and quality. Some are more challenging than others, but even the smallest changes can have a very positive impact when applied over time. Blow are some considerations:
Spend more time outside without sunglasses-natural light exposure during the day contributes to melatonin production in the evening to properly prepare us for sleep.
Minimize or eliminate screens 2 hours prior to sleep-blue light exposure beyond the daylight hours interferes with melatonin release.
When screens are unavoidable, consider wearing blue light blocking glasses to minimize this type of light exposure and/or activate the “night-shift” feature within the settings of your smart device to adjust for a warmer color spectrum that is less disruptive to melatonin release.
Aim for complete darkness- we have melatonin receptors throughout the body so light does not only affect receptors in the eyes.
Turn down the thermostat before sleep-keeping it a little cold at night decreases core body temperature which triggers sleep onset.
Commit to going to bed before 10pm (8pm or earlier for children)- majority of deep sleep is achieved in first few hours.
Commit to eating meals at regularly scheduled times as much as possible-other rhythms affecting metabolism such as exercise and meal-times influence our circadian rhythm too.
Stay active-exercise contributes to sleep drive (the body’s natural desire to rest) and helps regulate our core body temperature.
Recap
As we can see, sleep is a very complex process involving both the nervous and endocrine systems. However, many of the lifestyle and dietary adjustments we can make are not that complicated. Most of the nutrients that support sleep play a role in melatonin production and none work in a vacuum; each influencing one another and often derived from the same nourishing foods. Likewise, the habits we form around light exposure can benefit or burden this critical period of rest.
Disordered sleep conditions are on the rise and are likely due, in part, to the ubiquitous synthetic light generated by the relatively recent technological revolution. Still, plenty of research links poor sleep with negative health outcomes such as chronic disease and depression. If you struggle with sleep, and are serious about preserving your long-term health, you may consider seeking the help of a professional. There is much within your control!
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703169/